Kojic ester 2a-c was prepared via Claisen
Schmidt condensation followed by Steglich esterification with isolated kojic acid to yield 3a-c, whereas kojic ester (5a-d) was prepared via kojyl chloride  followed by addition of 4a-d to afford 5a-d (70-87%).
5), which should result from the Claisen
Rearrangement in HBP-AL .
Base catalyzed Claisen
condensation of 7a with 4-hydroxy benzaldehyde in presence of LiOH-[H.sub.2]O (Bhagat et al., 2006) gave compound 7b which upon deprotection (Vogel et al., 2008) yielded compound 7 (Scheme 1).
Finally, distillation was continued from a Claisen
flask up to 560[degrees]C.
condensation, Diels-Alder, Grignard, Hoffman rearrangement, Robinson-Schopf, Schotten-Bauman, Swern's oxidation, Ullman Ether synthesis, Williamson synthesis ...
The method is based on reaction of isopropylmagnesium chloride with 3-methyl-2-butenal, Claisen
rearrangement of the resulting alcohol via orthoacetate modification, and alkaline hydrolysis of the resulting ester.
This enzyme catalyzes the Claisen
rearrangement of chorismate to prephenate in the shikimate pathway, which is the first committed step in the biosynthesis of the aromatic amino acids phenylalanine and tyrosine.
5) of the F.I., it was pointed out from the early stages of its discovery that the first cyclization step resembles the Claisen
rearrangement reaction, which is known as a typical sigmatropy reaction.
Kitao, "New thermo-response dyes: coloration by the claisen
rearrangement and intramolecular acid-base reaction," Angewandte Chemie--International Edition, vol.
 have reported a biogenetic-like synthesis of racemic 1 from o-cinnamylphenols via the dehydrogenation of DDQ, while Subramanian and Balasubramanian  have synthesized racemic 1 from 1-arylprop-2-ynyl aryl ether in good yield by a facile Claisen